rlinford1

Don't have the specs here at home, I'll look next time I'm at the hanger. Would be interesting to calculate it.

My recollection is that the FAA and Lycoming determined that the engine was producing well over 200 hp at 38.5" hence their concern and the AD. Been a long time so my memory is fuzzy. Supposedly 33" was calculated to produce 200hp but who knows. I have not flown it sans turbo for 25 years so I don't have anything to compare it to but I would give up a little sea level performance for what I get at altitude. Lots of tall hard mountains and weather around Spokane. Also the documentation I have came from the STC holder and is not just the information that comes with the kit. Probably not something anyone needs until they are looking at some major work - it's essentially what they submitted to the FAA to get the STC in the first place. I never cataloged the whole thing but it's a lot of information - all I was looking for was servo porting info.

Just found this thread while looking for something else. I own an M20J with the original engine and Turbo Bullet still installed. I have flown it since the early 80's. No issues but I do run it carefully like any turbocharged engine. Time on engine since last rebuild is about 2400 hours. Annual last week compression test was good and a bore scope inspection revealed normal patterns on the valves and cylinder walls. I will run the engine past TBO as long as compression and inspections show it to be sound, and I certainly wont take the turbo system off - it works really well. And it's simple. Downside is you have to be careful not to over boost on takeoff but that's manageable if your on the ball. There are some "scare stories' out there you shouldn't listen to. Over-boosting was a real issue but if you run it at 33" your not straining the engine. Only issue is parts - my brother had to have the exhaust system rebuilt but that's what you deal with when your flying an old airplane. Also be darn sure your mechanic understands what they are looking at. We had one shop decide the fuel servo was set wrong so they sent it back to the factory to be re-ported. Took 6 months to get the STC information to straighten it out and get the plane flying again. When the engine goes you wont be able to get Lycoming to rebuild it but any competent shop with the correct specs can rebuild it with the shorter pistons. I also have all of the original STC documentation and drawings available. Because of liability I don't want to give them to anyone who is contemplating adding a new system to their aircraft but I have no problem sharing if you can prove you own a TurboBullet already. Only cost would be to scan the documents.